I'm developing a property website, using an additional product type (of property). Each property has a product price of zero, but has an additional attribute 'price' in a new table 'Property' which I would like to be able to display in the listing page (instead of Product Price).

I have attempted to edit product_listing.php to include:

// bof property price
if ($_GET['products_type']) = 6 {
$lc_price = zen_get_property_price($listing->fields['products_id']) . '<br />';
$lc_align = 'right';
$lc_text = $lc_price;
}


// eof property price

This is included directly above // more info in place of buy now
I've also added a file in extra_functions, property_price.php containing the following function:
function zen_get_property_price($product_id) {
global $db;
$free_tag = "";
$call_tag = "";

$final_display_price = $db->Execute("select products_id, price from " . TABLE_PROPERTY . " where products_id = '" . (int)$product_id . "'");
return $final_display_price . $free_tag . $call_tag;
}
The result of this 'upgrade' is a blank listing below the category heading with no erros displayed. I'm developing on localhost so can't give a link at this stage, but would appreciate any pointers as I've been staring at this most of the day now.